Shakes or Wobbles problem
2006 Infiniti G35 6 cyl Two Wheel Drive Manual 25000 miles
I have a G35 with aftermarket parts on it. It's stillen supercharged with full exhaust and MB rims. I purchased it with only 12500 miles. The tires were dryrotted and unevenly worn. I kept hearing a slight " rubbing/rotational" noise in the front left, that seemed to get worse on right turns. I recently replaced the tires with 245/45/18 yokohamas (original on this wheel was 235/45/18), had balance and alignment done. At speeds above 60MPH, the car would sporadically bounce, and the steering wheel would have a slight shake to it. I had my mechanic (he's my friend as well) recheck the balance, all good. He didn't think it was a bearing, since it only had 20K miles on it. He also thought I was crazy and hearing things, because he couldn't hear what I was hearing. I took it for a long drive over a weekend and at high speeds (around 80MPH) the entire chassis shook, especially when breaking. Thought maybe a caliper or rotors, so I replaced pads (needed), rotors but the calipers were fine. Shaking was less, but still there. The rubbing sound was still there. I checked the front wheels for sounds, and noticed the front left was making a clicking sound. I took it to the dealer to have them test drive it, and they thought I was crazy as well. That night, I took the front left wheel off, and the bearing was bad. Very loud clicking noise when I spun the hub assembly. I replaced it. Rebalanced the tires at a local shop since the steering wheel still vibrated. Upon getting the car back, took it for a test drive. At 70MPH, the car (seemed from rear end) shook violently. Slowed to 35, went away- back to 65, shook again. Seemed the rear wheels were going to fall off. Pulled over on highway, checked wheel, started backup and drove back to shop. They testdrove it, took the wheels back off (I couldn't see what work they did), remounted the wheels and said shaking was from road. Impossible. That shaking was so violent it sounded like a helicopter and felt like people were shaking the car. It was very dangerous. I didn't believe them, but when I took the car back, it ran perfectly. Maybe they over/under torqued the wheels, forgot to put the hub rings back on? Either way, once I got it back, No sounds, no vibration, no shaking. Drove it over the next -3 weeks for over 500 miles, all was good. On the way back home from a long drive (250mile round trip), a slight body/chassis shake came back. It's getting progressively worse. The steering wheel does not shake, but the chassis does, and it's again sporadic. I purchased new hub centric rings as one of the old ones had a crack in it. I plan to check the front right bearing and rear bearings. The rear bearings are tough because I am not able to spin the wheel easily, even in neutral. (I don't have a lift, only stands) All the suspension components look good. Beyond this, I dont' know what to check. I hate to keep putting money into it but the shaking is really annoying and I'm afraid it will just get worse and cause more damage to other car components. Yesterday it was raining here and the shaking was worse than usual. It's still not shaking as bad as it did before with the bad front-left bearing, but I definitely notice it. I don't understand what's going on. I know how the car feels and sounds when everything is working because for 500 miles, it was a perfectly smooth ride, with new tires and breaks. No shake at all when I break. Otherwise, the car runs perfectly. Any help would be greatly appreciated.
I would suggest checking the drive lines regarding the vibration.
When U-joints are stiff, they would cause vibrations and since the vibration is fom the body, the probable location would be the rear. Check the CV shaft inner joints for stiffness and lack of lubrication.
August, 20, 2010 AT 9:06 AM
Thanks for the suggestion. I did some research on what you said and as I was reading about it, I remembered something. After getting the tires replaced and balanced, but before replacing the left front bearing, I had my wife drive the car in circles very slowly as I walked alongside the car. I of course heard noises from the front left, but also heard sligth creeks/squeeks/clicks from the rear end, both sides, but they were very subtle. According to what I read, that falls in line with a symptom of what you said I should check. However, the article also said that if there are problems with a CV joint, they should be replaced rather than fixed. All this is certainly beyond my knowledge as of yet, so unless my repair manual (or you) suggest that it is an easy enough thing to do for a DIYer, I may be taking this to my mechanic friend. Do you have any thoughts on the matter? Should I replace the shaft, or just try greasing it? I saw I can find the part much cheaper at a junk yard, but not sure if that's adviseable. Is there a quick and easy way to check the CV shaft inner joints for stiffness and lack of lube?
Thanks so much for your help. If nothing else, I can at least point my mechanic to something for him to check since he couldn't feel or hear what I was feeling/hearing.
August, 20, 2010 AT 9:22 AM
The symptoms of clicking noises at rear does indicate possible bad joints.
For outer joints, they should be replaced but for inner joints, they can be disassembled to check for wear and if none found, repacked with grease and the boot replaced.
The usual signs of stiff inner CV joints are spilt grease at surrounding areas.
Next to check would be torn rubber boots.
The last thing to check would be for side play of the shaft. Push and pull at it side ways and note if there are any movement, should be minimal.
If you were to get used parts, ensure there are no signs of spilt grease, the oots are good and when twisting the joints, they move smoothly with little side play.
While you are there, remember to check the propeller shaft U-joints as well.